Utwory karbonu w podłożu monokliny przedsudeckiej

Abstract

THE CARBONIFEROUS FORMATIONS IN THE BASEMENT OF THE FORE-SUDETIC MONOCLINE Summary In the result of investigations carried on in the area of the Fore-Sudetic monocline, the Carboniferous deposits have been traced to occur under the Permo-Mesozoic formations (Ostrzeszów, Rawicz and Wichów). On comparison with the Silesian-Moravian Culm, and the faunistic data from Ostrzeszów, the deposits of the Tournaisian Lower-Visean, Upper Visean and Lower Namurian have been distinguished. On lithological data the deposits of profile at Wichów have been assigned to the Tournaisian-Lower Visean. These are arenaceous-gravelly and arenaceous ones. The profile under study amounts 480 m after reduction of great dips, being approximately of 45° (from 20 to 70°), and the thickness is about 330 m. The deposits may be paralellized with the Opavice (= Benesov) beds from East Sudetes. The equivalents of the Zawiszyce beds (= Moravian slates) have not so far been traced. The upper ones are arenaceous deposits from the lower part of the Ostrzeszów profile, which may correspond to the Kietlice beds (= Hradec greywackes). Their thickness amounts more than 300 m. They are overlain by clayey-arenaceous deposits from Ostrzeszów, containing fauna of Goniatites ex gr. granosus Portl., about 230 m in thickness, and end the profile of the Dinantian. A transition into the Silesian, known from Ostrzeszów, is not marked by an unconformity. Here are unstratified sandstones and siltstones, partly of marine, partly of continental origin. In the whole, they belong to the Lower Namurian. At Ostrzeszów, their thickness amounts about 200 m. To the Silesian there belong probably also grey siltstones occurring at the bottom of the Lower Permian, at Rawicz. In the author's opinion, the profile of Leśnia, so far referred to the Lower Carboniferous, also belongs to the Silesian. The deposits under discussion are folded. Magnitude of dip ranges from 10 to 70° and at Ostrzeszów it amounts approximately 20°, while at Rawicz, and Wichów, about 45°. It should be stressed that the deposits have undergone a strong, discontinuous tectonics, a fact proved by the tectonical breccia and considerable cracking of the series. The folding is of post-Namurian age. Here, the Sudetic phase bas not appeared. A connection of foldings in the area under study with the Góry Kruszcowe area, suggested in the paper, is based on the Westfalian age of the formations found in the German Democratic Republic and in the North Sudetic trough, so far referred to the Permian. The area that at the Dinantian and Lower Silesian times bad been a geosyncline, was stiffened during the Upper Silesian time due to the orogenic movements and got platform-like features, as expressed in lithological development of the Permian and Mesozoic formations. It is also possible that a part of the lower members of the deposits, so far described as Rotliegendes, may represent the Upper Silesian there.